The present invention provides a pigment dispersant: that is capable of remarkably ameliorating fluidity of a liquid product, such as an ink or a paint, which contains particles of a pigment, such as a black azo pigment, in a dispersed state; that can suppress aggregation of piment particles; that prevents occurrence of foreign substances; and that is capable of producing a colored article excellent in optical density. Provided is a pigment dispersant being a compound represented by the following formula (1).

##STR00001##

wherein R.sub.1 and R.sub.2 each independently represent a group obtained by eliminating one hydrogen atom from an amino group of an amine compound containing a basic nitrogen atom, and R.sub.3 and R.sub.4 each independently represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, or a hydroxy group.

The present invention relates to storage-stable dye salts, solutions and compositions thereof a process for their preparation and their use for dyeing and/or printing substrates.

Described herein are novel azo-benzene type chromophores. The chromophores are useful in photochromic compositions comprising a polymer matrix and a chromophore, wherein the chromophore is a novel azo-benzene type structure. The photochromic composition is photoresponsive upon irradiation by at least one wavelength of laser light across the visible light spectrum. Photochromic devices which comprise the novel azo-benzene type chromophore compound show significantly higher photoinduced birefringence, higher diffraction efficiency, and brighter images than devices that comprise well known azo-benzene chromophores. The photochromic composition may include a liquid crystal.

Described herein are novel azo-benzene type chromophores. The chromophores are useful in photochromic compositions comprising a polymer matrix and a chromophore, wherein the chromophore is a novel azo-benzene type structure. The photochromic composition is photoresponsive upon irradiation by at least one wavelength of laser light across the visible light spectrum. Photochromic devices which comprise the novel azo-benzene type chromophore compound show significantly higher photoinduced birefringence, higher diffraction efficiency, and brighter images than devices that comprise well known azo-benzene chromophores. The photochromic composition may include a liquid crystal.

Described herein are novel azo-benzene type chromophores. The chromophores are useful in photochromic compositions comprising a polymer matrix and a chromophore, wherein the chromophore is a novel azo-benzene type structure. The photochromic composition is photoresponsive upon irradiation by at least one wavelength of laser light across the visible light spectrum. Photochromic devices which comprise the novel azo-benzene type chromophore compound show significantly higher photoinduced birefringence, higher diffraction efficiency, and brighter images than devices that comprise well known azo-benzene chromophores. The photochromic composition may include a liquid crystal.

The present invention relates to storage-stable dye salts, solutions and compositions thereof a process for their preparation and their use for dyeing and/or printing substrates.

The present invention relates to the field of isomeric mixture of reactive dyes that are suitable for the dyeing or printing of nitrogen-containing or hydroxy-group-containing fibre materials and yield on such materials dyeings or prints having a good build-up behaviour, a high fixation rate, good washing off properties of the unfixed dyes and good all-round fastness properties, as well as a good stability to various dyeing parameters such as a good bath stability. Furthermore, the present invention relates to a process for dyeing or printing of nitrogen-containing or hydroxy-group-containing fibre materials, wherein the isomeric mixture of reactive dyes according to the invention is used. The isometric mixture of the present invention comprises at least an isomer of formula (Ia) and an isomer of formula (Ib).

##STR00001##

The present invention relates to the field of isomeric mixture of reactive dyes that are suitable for the dyeing or printing of nitrogen-containing or hydroxy-group-containing fibre materials and yield on such materials dyeings or prints having a good build-up behaviour, a high fixation rate, good washing off properties of the unfixed dyes and good all-round fastness properties, as well as a good stability to various dyeing parameters such as a good bath stability. Furthermore, the present invention relates to a process for dyeing or printing of nitrogen-containing or hydroxy-group-containing fibre materials, wherein the isomeric mixture of reactive dyes according to the invention is used. The isometric mixture of the present invention comprises at least an isomer of formula (Ia) and an isomer of formula (Ib). ##STR00001##